1. Field of the Invention
The present invention relates to an apparatus and method for In-phase/Quadrature-phase (I/Q) mismatch calibration, and more particularly, to an apparatus and method for I/Q mismatch calibration with more rapidity and reliability using the symmetry of continuous wave signals.
2. Description of the Related Art
A receiver of a high-speed wireless communications system causes signals received via an antenna to be demodulated through a Radio Frequency (RF) terminal and an Intermediate Frequency (IF) terminal, and then performs restoration of the signals.
The RF and IF terminals process the signals received via the antenna and perform frequency down converting and signal strength amplifying functions so as to obtain desired signals.
The RF and IF terminals utilize various analog devices including mixers and amplifiers. These devices satisfy standards to a certain degree, but there is a limitation on the coverage of standards. Due to imperfect insulation and orthogonality between the devices, input signal degradation may occur.
One of the reasons for signal degradation is a mismatch between an In-phase (I) channel and a Quadrature-phase (Q) channel.
The mismatch between the I-channel and the Q-channel is caused by each device's insulation state and the failure to generate signals having a perfect 90-degree phase difference between the I-channel and the Q-channel. The mismatch between the I-channel and the Q-channel is a factor in the degradation of the performance of a modem's demodulator that is intended for signal restoration. Therefore, there is a need for a solution to remove the mismatch between the I-channel and the Q-channel.